The hair follicle, which is grown from a lower part of the primitive epidermis and extends into a deeper skin layer, is a distinctive organ found in mammalian skin. A cell plug known as a follicle or dermal papilla cell exists in the base of the hair follicle (Stenn and Paus, Physiol. Rev., 81: 449 (2002)), and the papilla is essential in the normal circulation of the hair follicle (Oliver, Embryol. Exp. Morph. 15: 3311 (1966); and Oliver, Embryol. Exp. Morph. 16: 231 (1966)) and the growth of the hair shaft. The hair shaft is a thread-shaped structure formed of epithelial cells composed of keratin filaments and filament-aggregating proteins tightly attached thereto.
Human hairs fall out and again produce while cyclically repeating anagen, catagen, and telogen phases. The cycle of growth in the hair cycle is determined by regulation of hormones or other growth factors. Severe stress or malnutrition may advance the catagen and telogen phases, leading to severe hair loss (American Journal of Pathology, 162(3)(2003), (Arck, Petra Clara; Handjiski, Bori)).
In cases of male-pattern baldness, the hair follicles at the front and top of the scalp are sensitive to androgen. Thus, male-pattern baldness corresponds to the minimization of hair follicles rather than the destruction of hair follicles, and is caused by excessive secretion of the male hormone androgen. The excessive secretion of androgen results in the activation of 5-α reductase, converting testosterone into dihydrotestosterone (DHT). The resulting dihydrotestosterone shortens the cycle of hair growth and miniaturizes hair follicles, decreasing the number of thick strong adult hairs, leading to hair loss.
In general, hair loss increases with aging. For example, different disorder conditions, such as scar conditions associated with cicatricial alopecia, burns or compression injuries, may cause severe hair loss. Several substances as medicaments have been used to treat such a hair loss phenomenon, but the medicaments are expensive or cause several adverse effects.
In addition, these medicaments have drawbacks in that the sustained use thereof is required; hair loss again occurs when the use thereof is stopped; there are individual differences in efficacy; and side effects vary from person to person.
Furthermore, raw materials used as cosmetics have an advantage of being inexpensive, but their efficacy is not great since they contain ingredients derived from plant extracts. Therefore, there is an increasing need in the art for novel effective ingredients that are more economical in terms of costs.
Two available drugs known so far (minoxidil and finasteride) might delay additional hair loss, but do not induce the regeneration of new hair follicles. Among hair cosmetics, a lot of anti-hair loss products using plant extracts and the like have also been released.
For example, the products using plant extracts and the like that have been developed include: products containing extracts of sophora root, chili pepper, swertia, morus bark, morus leaves, ginseng, licorice, peony, foxglove, fennel, cornus fruit, garlic, and the like; products wherein a composition containing xanthines and growth hormones is added to improve cellular metabolism suppressed by excessive dihydrotestosterone and stimulate hair growth induced by growth hormones, thereby preventing hair loss and attaining hair production, leading to a hair growth stimulating effect; hair production stimulating products that supply nutrients to the scalp and hair through the development of products containing minerals, vitamins, and extracts of green tea, rosemary, mugwort, or licorice, in order to stimulate hair production and hair growth, and have effects in the prevention of hair loss and the stimulation of hair growth; and products for male-pattern baldness wherein the substances, such as vitamin B, vitamin C, vitamin D, vitamin E, nicotinic acid, pantothenic acid, biotin, and folic acid, are mixed with plant extracts to inhibit 5-α reductase, thereby preventing the production of dihydrotestosterone in the metabolism of male hormones and helping hair metabolism. However, products that affect even the production of new hair are difficult to find.